Babkevich, P.Jeong, M.Matsumoto, Y.Kovacevic, I.Finco, A.Toft-Petersen, R.Ritter, C.Mansson, M.Nakatsuji, S.Rønnow, Henrik M.2016-07-192016-07-192016-07-19201610.1103/PhysRevLett.116.197202https://infoscience.epfl.ch/handle/20.500.14299/127716WOS:0003760115000031605.03443We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet LiYbF4. For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent -0.25(1). The exponents agree with the 2D XY/h(4) universality class despite the lack of apparent two-dimensionality in the structure. The order-parameter exponent for the quantum phase transitions is found to be 0.35(1) corresponding to (2 + 1)D. These results are in line with those found for LiErF4 which has the same crystal structure, but largely different T-N, crystal field environment and hyperfine interactions. Our results therefore experimentally establish that the dimensional reduction is universal to quantum dipolar antiferromagnets on a distorted diamond lattice.MPBHtext::journal::journal article::research article